Die set



I i Feb. 2,51943. w. E. DALBY DIE sm v Filed April 14, 1941' 2 Sheets-Sheet 2 Zgg.

l: -xN

lullin Patented Feb. 2, 1943 DIE SET Walter E.

Dalby, Detroit, Mich, assignor m Chrysler Corporation, Higland Park, Mich., a

corporation of Delaware Application April 14, 1941, Serial No. 388,363

(Cl. 'iS-60) 3 Claims.

This invention relates to means for manufacturing articles of sintered metal.

It is the principal object of the invention to provide means for forming such articles with extreme accuracy and uniformity.

In the following description, apparatus for forming the cuter rotor of a Gerotor pump is described, but it is desired to point out that the apparatus and method are applicable to the forming o-f articles of other shapes.

Gerotor pumps comprise inner and outer rotors which rotate relatively to one another and. to the pump casing. The size and shape of both rotors must be held within extremely close tolerances during manufacture and considerable diiiculty has been experienced in holding these tolerances in quantity production.

I have found that satisfactory rotors can be made in quantity at low cost by the following method; the nely divided material (which may be iron, brass or other suitable material) is first briquetted, then sintered, and then subjected to a rough sizing operation. Then, the article is subjected to a finishing or coining operation during which it is formed with extreme accuracy with respect to size and concentricity. This lasi-l operation is a particularly important one and requires a die set which is extremely rigid. The die set disclosed and claimed herein permits rapid operation and will hold the size and concentricity of the iinished article to within .0005 inch. This is accomplished by my novel and improved arrangement wherein certain interengaging parts of the die are brought into engagement in definite sequence.

In the drawings accompanying the description:

Fig. 1 illustrates the die set just as the ram is starting to push the work in the die, the up position of the ram being shown in broken lines.

Fig. 2 illustrates the parts with the ram in down position.

Fig. 3 is a sectional view along the line 3 3 of Fig. 2.

Fig. 4` is a plan View of the formed article.

Fig. 5 is a sectional View along the line 5-5 of Fig. 4.

In the present instance, the workpiece consists of an outer Gerotor element which is illustrated in Figs. 4 and 5. The element I0 is designed to run in mesh with an inner rotor having one less tooth and both rotors are adapted to be enclosed in a pump housing. In order to give the required pump efciency, the upper and lower surfaces of the element Ii) must be iiat and parallel, the outer periphery must be round and concentric about the axis of the piece and the inner tooth surface must be concentric .with the outer peripheral surface.

The element Ill is rst briquetted, then sinftered, then subjected to a rough sizing o-peration before being placed on the formed plug II which forms part of one of the die sections. The plug H is` shown in section in Fig. 3 and comprises a central portion I2 having a shape identical with that of the inner rotor with which the finished workpiece is designed to run, and upper and lower reduced portions I3 and I4. The lower portion I4 is rigidly supported in a 'die adaptor I5 and is secured thereto -by a bolt I6. The head of the latter is seated in a removable plug I'I which carries the knockout pins I8, the plug being secured to the adaptor by set screws I9. The upper reduced portion I3 is adapted to be received by a cylindrical hole 2i! formed in the punch adaptor 2l which carries the die punch 22. The punch 22 is removably fastened to the adaptor 2| by screws 23.

The punch adaptor 2| is carried by a ram 24, to which it is removably secured by a ring 25, and the ram is adapted to be mounted in a suitable press or other machine (not shown).

Fastened by screws 26 to the die adaptor I5 is a, formed die member 21 and slidably disposed in the space between the member 2l and the formed portion of the plug II is an insert 28 which is shaped identically with the finished workpiece.

A knockout plate 29 rests on a knockout sleeve 30, the latter being adapted for reciprocation in timed relation with the ram 24 as will be explained further on.

All of the parts of the die set are made of relatively heavy section and the diameters a, b, c, d and e, as well as the faces f and g, are formed with extreme accuracy.

'Ihe coining operation takes place as follows:

The workpiece I0 is first placed over the plug I3 where it rests on the insert 28, the ram 24 being in the up position as shown in broken lines in Fig. 1. The plug I3 has a tapered portion 3I which permits the work to be located angularly. The insert 28 is held up by knockout pins I 8 of which there are three, the pins in turn resting on the knockout plate 29. The knockout sleeve 30 is preferably actuated to its up position by a machine element (not shown) and held up by a spring when the element is retracted.

When the press is tripped, the ram 24 descends from its broken line position to the full line position of Fig. 1 where the punch 22 engagesthe work I0 and presses it into the die 21. The positions of the parts at the bottom of the stroke of the ram are illustrated in Fig. 2.

It will be seen that as the ram descends, die 21 and formed plug Il are held concentric in die adaptor l5 and at the instant the punch 22 engages the work I0, the diameter a, of punch adaptor 2| engages diameter b of die 21 and diameter c of punch adaptor 2| engages diameter d of the plug Il. Plug Il is thus held concentric with diameter e of the die during the pressing operati-on and concentricity of the nished part is assured.

At the bottom of the stroke of the ram face f of the punch adaptor 2l engages face g of the die 21 and this assures squareness of the upper and lower faces of the work with relation to the hole and the outer diameter thereof and also vparallelism of the faces.

I claim:

1. In a die set for sizing preformed articles, a reciprocable ram; a punch carried by said ram; a stationary die member; a formed plug; means for rigidly holding said plug and die member in spaced relationship, the space therebetween being adapted to receive a workpiece; and means carried by said ram for engaging said plug upon descent of the ram thereby to hold said plug and punch in rigid relationship during closing Vor" the die set.

2. In a die set for sizing preformed articles, a reciprocable ram; a punch carried by said ram; a formed plug; a stationary die member; means for rigidly mounting said plug and die member in spaced relationship whereby the space between them is adapted to receive a workpiece; means carried by said ram for engaging said plug upon descent of the ram whereby concentricity between the plug and punch is maintained during the working stroke.

3. In a die set for sizing preformed articles, a reciprocable punch; a punch adaptor for carrying said punch; a die member having an internal hole adapted to receive said punch and an external cylindrical portion adapted to be received by said punch adaptor, said die member and said punch ,adaptor being provided with flat surface portions adapted for engagement at the endof the working stroke.

WALTER E. DALBY. 

